An economic term that describes happiness and is hard to measure in numbers is .

cost
incentive
utility

utility

Explanation:

   Utility

is the satisfaction derived in the consumption of a particular commodity. For example, if you are coming from school so tired and thirsty, you decided to visit a friend on your way home. he offered you a very cold soft drink, you drank the drink immediately, you will feel so refreshed and satisfied that is utility. unlike if your friend just offered you a warm drink , you might take it but you will not derive a satisfying experience unlike the cold drink. so utility describes as the satisfying power of a commodity.

answer; collective security;